The goal of the proposed research is to identify variables related to classical conditioning that may contribute to the rapid escalation and compulsivity of drug-taking and drug-seeking behavior observed in human drug abusers. The first of the proposed experiments will examine the ability of drug-associated stimuli to attract the organism and elicit approach and contact behavior. This experiment will explore the variables relevant to producing auto shaping (Brown & Jenkins, 1968) with cocaine as the reinforcer. A second experiment will determine the extent to which behavior elicited by drug-associated stimuli is compulsive and insensitive to instrumental contingencies. An omission training procedure (e.g., Williams & Williams, 1969) will be used where approaching and contacting the drug-paired stimulus results in a loss of reinforcement. A third experiment will examine the ability of behavior elicited by drug-associated stimuli to enhance rates of drug-seeking and drug-taking behavior. This will be accomplished by using a behavioral contrast procedure (Reynolds, 196 1), where responding will be maintained by cocaine self-administration.